This invention relates to a hydrostatic auxiliary power steering mechanism, especially for motor vehicles. The auxiliary power steering mechanism contains a metering device and a control valve which channels the pressure medium which is fed to a steering motor by a variable displacement or a constant pump via a current divider valve. In the pressure line, there is provided an orifice by virtue of whose pressure difference one can activate an adjusting device of the variable displacement pump or of the current divider valve. The feed from the pressure into the valve borehole is guided via a central piston collar which is arranged on a valve piston that is movably positioned in the valve borehole.